Methods of and apparatus for drawtwisting textile yarns or filaments

ABSTRACT

A method and apparatus for drawtwisting textile yarns or filaments wherein the yarns or filaments are drawn in a drawing zone and then wound by a ring and traveller upon a rotating bobbin carried by a driven spindle to form a wound package, the diameter of which continuously increase during the winding operation. A predetermined spindle speed program drives the spindle initially at a speed lower than an predetermined maximum spindle speed at the commencement of a package build, gradually increases the spindle drive speed to said maximum speed during an initial portion of the build, and then gradually decreases the spindle drive speed throughout the whole of, or a part of, the remainder of the package build.

United States Patent 11 1 Scowcroft 14 1 Apr. 3, 1973 54] METHODS OF AND APPARATUS FOR 1,965,163 7 1934 Truslow ..57 93 DRAWTWISTING TEXTILE YARNS QR 3,451,209 6/1969 Bisset et al ..57/93 X FILAMENTS FOREIGN PATENTS OR APPLICATIONS [75] Invent: swwcmfi England 1,142,603 9/1957 France ..s7/93 [73] Assignee: T.M.M. (Research) Limited, Lancashire, England a Primary Examiner-Donald E. Watkins [22] Filed: oct- 19, 1970 Attorney-Watson, Cole, Grindle & Watson [21] Appl. No.: 82,017 [57] ABSTRACT A method and apparatus for drawtwisting textile yarns [30] Foreign Application Priority Data or filaments wherein the yarns or filaments are drawn in a drawing zone and then wound by a ring and Oct. 20, Great Bntam traveller p a rotating bobbin carried a driven spindle to form a wound package, the diameter of [52] US. Cl... ..57/93, 57/156 which continuously increase during the winding opera Int. Cl. ip A predetermined pi speed p g drives [58] Field Of Search ..57/92, 93, 94, 156 the spindle initially at a speed lower than an predetep mined maximum spindle speed at the commencement [56] References Cited of a package build, gradually increases the spindle drive speed to said-maximum speed during an initial UNITED STATES PATENTS portion of the build, and then gradually decreases the 3,526,244 9/1970 Joy .;..57/93 X spindle drive speed throughout the whole of, or a part 3,325,985 6/1967 Bucher ..57/93 of, the remainder of the package build. 3,357,655 12/1967 lwnicki et al. ....57/94 X 630,567 8/1899 Robb et a1. ..57/93 X 18 Claims, 5 Drawing Figures PATENIEDAPRB ms 3.724.197

sum 1 or 3 METHODS OF AND APPARATUS FOR DRAWTWISTING TEXTILE YARNS R FILAMENTS The present invention relates to methods of and apparatus for drawtwisting yarns or filaments in which the yarns or filaments are subjected to drawing in a drawing zone and then wound by means of a ring and traveller upon a rotary package carried by a driven spindle is particularly concerned with such drawtwisting methods and apparatus in which the diameter of the wound package continuously increases during the winding operation.

It is known in drawtwisting machines for processing continuous filaments of synthetic materials that, when yarn is being delivered at constant speed to a bobbin by way of a ring and traveller and the spindle speed remains constant, the traveller and balloon speed increase in direct ratio to the increasing diameter of the yarn package being wound on to the bobbin. This increasing traveller and balloon speed has a direct efi'ect on the tension in the yarn being processed and it is possible for the tension on the yarn to become so great as to have a detrimental eifect on both the quality of the yarn and the package being produced. In addition, the traveller speed can become so high as to cause excessive wear and burning of the traveller, or the deposition of traveller material on the ring surfaces, giving rise to malfunction of the traveller on the ring.

It has hitherto been proposed slowly to reduce the spindle speed during the building of a package on the bobbin to arrive at winding conditions approximating those giving either constant yarn tension or, if required, as an alternative, constant balloon speed. Experiments have shown that a progressive reduction in spindle speed from start to finish of a build does not provide the correct or ideal tension control program, particularly when small diameter bobbin tubes are operating within rings permitting maximum permissible diameter of finished packages. Under such conditions, the yarn traveller angle, that is to say, the angle between the yarn path from the periphery of the empty bobbin to the traveller and the yarn path from the traveller to the lappet balloon guide becomes very acute and provides additional frictional resistance to the movement of the yarn through the traveller. This additional frictional resistance increases yarn tension considerably above that normally resulting from the traveller action on the ring, centrifugal forces and windage acting on the ballooning yarn.

It is an object of the present invention to provide an improved method of and apparatus for drawtwisting textile yarns and filaments, in which the above-mentioned drawback is avoided.

According to one aspect of the present invention, there is provided in a method of drawtwisting textile yarns or filaments in which the yarns or filaments are subjected to drawing in a drawing zone and then wound by means of a ring and traveller upon a rotating bobbin carried by a driven spindle to form a wound package the diameter of which continuously increases during the winding operation, the step of causing the spindle to follow a predetermined spindle speed program in which at the commencement of a build of a package the spindle initially runs at a speed lower than a predetermined maximum spindle speed, gradually increases in speed to said maximum speed during an initial portionof the build and then gradually decreases in speed throughout the whole of or a part of the remainder of the build of the package.

In accordance with another aspect of the invention, there is provided apparatus for draw-twisting yarns or filaments comprising yarn or filament drawing means for drawing the yarns or filaments, a rotary spindle, a ring and traveller by means of which the yarns or filaments delivered from said drawing means are wound on to a rotating bobbin on the spindle toform a wound package thereon, the diameter of which continuously increases during the winding operation, and spindle speed adjusting means for adjusting the speed of rotation of the spindle under the control of a speed-programing element defining a predetermined spindle speed program, whereby the spindle is in operation caused at the commencement of the build of a package to run at a speed lower than a predetermined maximum spindle speed, gradually to increase in speed to the maximum spindle speed during an initial portion of the build and then gradually to decrease in speed throughout the whole or a part of the remainder of the build of the package. I I

One embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a schematic perspective view of a drawtwister according to the invention;

FIG. 2 is a graph showing the programed change of spindle speed during the build of a package on the drawtwister shown in FIG. 1,

FIG. 3 is a side elevation of a package built by the drawtwister shown in FIG. 1 and controlled in accordance with the spindle speed program illustrated in FIG. 2, I

FIG. 4 is a block schematic diagram of a driving ar rangernent for the draw and feed rolls and the spindle of the drawtwister shown in FIG. 1, and

FIG. 5 is a schematic plan view of a cam for the drivingarrangement shown in FIG. 4.

Referring first to FIG. 1, undrawn yarn Y of synthetic continuous filaments is withdrawn from a creel package 1 through an eyelet 2 and taken over snubbing pin 3 which serves to pretension the yarn. The yarn Y then passes through the nip of a feed roll 4 co-operating with cot roll 5 after which it is taken around a heated top draw roll 6 and separator roll 7 in a succession of loops. The peripheral speed of top draw roll 6 is greater than the peripheral speed of rolls 4 and 5 in order to effeet a drawing action on the yarn. The yarn Y is then subjected to further drawing by passing it over a heater plate 8 and around a bottom drawroll 9 and a separator roll 10 in a succession of loops. Drawing of the yarn is efiected by giving a higher peripheral speed to the bottom drawroll 9 than top drawroll 6.

After drawing, the yarn passes through a lappet guide 11 and a balloon control ring 12 to be wound on a package 13 by a ring and traveller arrangement 14. Rotation of the spindle 15 is effected by a driving tape 16 in contact with a spindle driving pulley 17.

A driving arrangement for driving the draw rolls 6 and 9 and the feed roll 4, as well as the spindle 15 will now be described with reference to FIG. 4. In the driving arrangement, a first DC electric motor 111, hereinafter referred to as the draw roll motor, is provided for driving the draw rolls 6 and 9 and the feed roll 4, a second DC electric motor 112, hereinafter referred to as the spindle motor, is provided for driving the spindle 15. Common armature voltage control means are provided to control the armature voltages applied to the two motors 111 and 112, and field voltage control means for controlling the field voltages applied to the two motors. The field voltage control means includes automatic means for adjusting the field voltage of the spindle motor 112 by means of a rotary cam 121 which is arranged to rotate once during each package build and which has a profile drivingly engaging a control element controlling the field voltage applied to the spindle motor.

The profile of the rotary earn 121 is illustrated in F l6. and is such as to provide the variation in spindle speed throughout the build of the package according to the program illustrated in FIG. 2, for a constant yarn delivery speed from the draw roll 9 of 3000 feet per minute. According to the program, the spindle is caused at the commencement of the build of a package to run at a speed of 8,250 r.p.m. which is lower than the predetermined programed maximum spindle speed of 8,350 r.p.m., then to increase in speed for a period of 60 minutes during an initial portion of the build to the programed maximum speed and then gradually to decrease in speed for a period of 730 minutes during the remainder of the build of the package which is completed in a total spinning time of 790 minutes.

By controlling the speed of the spindle according to the program illustrated in FIG. 2, not only is easier starting of each build achieved, but yarn sloughing problems are diminished in the early stages of the package build because of improved tension control.

The program illustrated in FIG. 2 of the drawings as applied to the particular bobbin build illustrated in FIG. 3 gave a constant tension in the yarn from start to finish of the build, but it will be appreciated that the program may be varied to suit any other particular set of circumstances. I

Referring again to FIG. 4 of the drawings, the armaturewindings of each of the motors 111 and 112 are connected in parallel to a DC output terminal .113 'of a silicon controlled rectifier unit SCRl, to an input ter- The voltage for the field windings of the draw roll motor 1 1-1 is also derived from the unit SCRl at output terminal 116 and a third control element 118 is provided for manually varying'the DC field voltage at the terminal.

The field windings of the spindle motor 112 are energized by a DC field voltage obtained from an output terminal 119 of a second silicon controlled rectifier unit SCR2 to an input terminal 120 of which the AC voltage from the mains supply 115 is fed. The further rectifier unit SCR2 is provided with a field voltage control element (not shown) which can be adjusted to vary the DC field voltage appearing at terminal 119 and applied to the spindle motor 112. The field voltage control element of the unit SCR2 comprises a'rectilinear potentiometer the wiper of which is driveably engaged by the profile of the earn 121. The output shaft of the spindle motor 112 is provided with a tacho-generator 122 which generates a feedback signal which is fed back to the second rectifier unit SCR2 as a negative feedback signal in opposition to the programed field voltage to provide a closed loop field control for the motor 112. v

For a predetermined set of operating conditions for the machine, the basic running speed is first set by overall adjustment of the armature voltage by the armature voltage control element of the first rectifier unit SCRl. The required difference in the speeds of the draw roll motor and the spindle motor is then obtained by manual adjustment of the field voltage control element of the rectifier unit SCRl which results in a change in speed of the draw-roll motor 111. The appropriate cam 121, as shown in FIG. 5, for controlling the field voltage to the spindle motor 112 is fitted to provide the required variation in spindle speed during the build of the package, and the machine is then ready for operation.

Upon starting up of the machine, the control element governing the crawl speed is set in response to a signal minal 114 of which is fed an AC voltage'from a mains supply 115. The rectifier unit SCRl includes a first adjustable control element (not shown) by means of which the DC output voltage at the terminal 113 of the unit can be preset to provide basic running speeds for the two motors 111 and 112 and a second adjustable control element (not shown) which can be switched between two positions in one of which it gives rise to an armature voltage providing a very low or crawl speed for the two motors 111 and 112 to assist threading up of the machine and in the other of which the armature voltage provides the desired basic running speeds for the two motors, change over from crawl to running speed being carried out. automatically by the further control element over a preselected time interval which may, for example, be from 10 to 30 seconds. The output shaft of the draw roll motor 111 is coupled to drive a tacho-generator 117, the output of which is fed back to the rectifier unit SCRI as a negative feedback signal to form a closed loop armature control for the motor 1 1 1 from a machine control unit CU so that the machine runs at crawl speed for threading up the yarns. After threading up the crawl speed control is switched over and the machine automatically brought to normal running speed in a controlled manner. The cam 121 controlling the field-voltage to the spindle motor 112 automatically commences its excursion and the spindle speed is programed by it throughout the package build.

'The basic speed of the machine is always set by the draw roll motor 111, which determines the delivery speed of yarn to the spindles.

The crawl speed control should preferably be adjustable between 25 and r.p.m., although the accuracy of speed control in crawl is not important.

The electrical linking of the armatures of the two motors 111 and 112 causes the spindle and feed and draw roll drives to accelerate substantially in ration, and certainly good enough for drawtwister drives. On deceleration, the generation created by both armatures will keep them reasonably in rau'o.

A resistor 123 is included in the armature circuit of the draw roll'motor 111 to allow the spindles to lead on starting and is arranged automatically to cut out when the motors reach normal running speed.

A resistor 124 provides dynamic braking of the motors 111 and 112 on deceleration, being automatically connected across the armatures of the two motors in response to a signal from the control unit CU when the machine is switched off.

Overlead switches 125 and 126 are provided in the armature circuits of the two motors 111' and 112 and can be reset by a signal from the control unit CU.

In the embodiment of the invention hereinbefore specifically described, the spindle speed "program is one in which the spindle speed is increased during an initial portion of the build during a time interval representing about 7 percent of the total package building time. For some purposes it may be desirable to reduce the time interval to about 4 percent of the total package building time and a cam of the shape illustrated in FIG. 5 may then be provided in which the initial profile subtending an angle of 27 is replaced by one subtending an angle of only The program for the spindle speed would normally be decided by the user of the drawtwister to suit the processing of a particular yarn and the time during which the initial portion of the build would take place would vary according to the denier ofthe yarn being processed. A cam of suitable profile would therefore be made to meet the particular requirements of the user.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a method of drawtwisting textile yarns or filaments in which the yarns or filaments are subjected to drawing in a drawing zone and then wound by means of a ring and traveller upon a rotating bobbin carried by a driven spindle to form a wound package the diameter of which continuously increases during the winding operation, the step of causing the spindle to follow a predetermined spindle speed program independent of the drawing speed of said yarns or filament in which at the commencement of a build of a package the spindle initially runs at a speed lower than a predetermined maximum spindle speed, gradually increases in speed to said maximum speed during an initial portion of the build, and then gradually decreases in speed throughout at least part of the remainder of the build of the package.

2. A method according to claim 1, wherein the program is such that the spindle speed increases during the said initial portion of the build during a time interval representing not less than 4 percent of the total package building time.

3. A method according to claim 1, wherein the program is such that the spindle speed increases during the said initial portion of the build during a time interval representing not less than 7 percent of the total package building time.

- 4. A method according to claim 1, wherein the spindle speed increases during the initial portion of the build during a time interval of one hour or more.

5. A method according to claim 1, wherein the speed of the spindle decreases throughout the whole of the said remainder of the build of the package.

6. A method according to claim 1, wherein the spindle speed increases at a constant rate during said initial portion of the build and decreases at constant rate throughout the whole of the said remainder of the build of the package.

7. A method according to claim 1, wherein the drawn yarns or filaments are delivered from said drawing zone at a constant delivery speed.

8. A method according to claim 7, wherein said delivery speed is substantially equal to 3000 feet per minute, the spindle speed increases linearly from 8,250

r.p.m. to a maximum spindle speed of 8,350 r.p.m. in a time of approximately 1 hour, and then the spindle speed decreases linearly to 7,650 r.p.m. in a time of approximately 730 minutes.

9. Apparatus for drawtwisting yarns or filaments comprising: drawing means for drawing said yarns or filaments, a rotary spindle, a ring and traveller for winding said yarns or filaments delivered from said drawing means on to a rotating bobbin on said spindle to form a wound package thereon, the diameter of said package continuously increases during the winding thereof, and spindle speed adjusting means for adjusting the speed of rotation of said spindle independent of the speed of said drawing means and including a speedprograming element defining a predetermined spindle speed program for controlling said spindle speed adjusting means, whereby at the commencement of and during an initial time interval of the build of a package said spindle runs at a speed lower than a predetermined maximum spindle speed, during an initial portion of the build said spindle speed gradually increases to a maximum spindle speed, and then said spindle speed gradually decreases throughout at least part of the remainder of the build of said package.

10. Apparatus according to claim 9, wherein said programing element defines a spindle speed program in which the spindle speed increases during said initial time interval of the build, and said initial'time interval representing not less than 4 percent of the total package building time.

11. Apparatus according to claim 9, wherein said programing element defines a spindle speed program in which the spindle speed increases during said initial time interval of the build, and said initial time interval representing not less than 7 percent of the total package building time.

12. Apparatus according to claim 9, wherein said programming element defines a spindle speed program in which the spindle speed increases during said initial time interval of the build, and said initial time interval is 1 hour or more.

13. Apparatus according to claim 9, wherein said programing element defines a spindle speed program in which the spindle speed decreases throughout the whole of the said remainder of the build of the package.

14. Apparatus according to claim 9, wherein said speed-programing element defines a spindle speed program in which the spindle speed increases at a constant rate during said initial time interval of the build and decreases at a constant rate during the whole of the said remainder of the build of the package.

15. Apparatus according to claim 9, wherein said yarn or filament drawing means is arranged to deliver drawn yarns or filaments at a constant delivery speed.

16. Apparatus according to claim 15, wherein said programing element defines a spindle speed program wherein said drawing means provides a deliveryspeed of the drawn yarns or filaments substantially equal to 3000 feet per minute, the spindle speed increases linearly from 8,250 r.p.m. to a maximum spindle speed of 8,350 r.p.m. during said initial time interval, and the spindle speed decreases linearly throughout the remainder of the build of said package to 7,650 r.p.m.,

18. Apparatus according to claim 9, wherein said programing element comprises a rotary cam which rotates once during each package build and which has a profile representing said program, and said spindle speed adjusting means further includes a control element engaging with said programing element to vary the spindle speed in accordance with said program. 

1. In a method of drawtwisting textile yarns or filaments in which the yarns or filaments are subjected to drawing in a drawing zone and then wound by means of a ring and traveller upon a rotating bobbin carried by a driven spindle to form a wound package the diameter of which continuously increases during the winding operation, the step of causing the spindle to follow a predetermined spindle speed program independent of the drawing speed of said yarns or filament in which at the commencement of a build of a package the spindle initially runs at a speed lower than a predetermined maximum spindle speed, gradually increases in speed to said maximum speed during an initial portion of the build, and then gradually decreases in speed throughout at least part of the remainder of the build of the package.
 2. A method according to claim 1, wherein the program is such that the spindle speed increases during the said initial portion of the build during a time interval representing not less than 4 percent of the total package building time.
 3. A method according to claim 1, wherein the program is such that the spindle speed increases during the said initial portion of the build during a time interval representing not less than 7 percent of the total package building time.
 4. A method according to claim 1, wherein the spindle speed increases during the initial portion of the build during a time interval of one hour or more.
 5. A method according to claim 1, wherein the speed of the spindle decreases throughout the whole of the said remainder of the build of the package.
 6. A method according to claim 1, wherein the spindle speed increases at a constant rate during said initial portion of the build and decreases at constant rate throughout the whole of the said remainder of the build of the package.
 7. A method according to claim 1, wherein the drawn yarns or filaments are delivered from said drawing zone at a constant delivery speed.
 8. A method according to claim 7, wherein said delivery speed is substantially equal to 3000 feet per minute, the spindle speed increases linearly from 8,250 r.p.m. to a maximum spindle speed of 8,350 r.p.m. in a time of approximately 1 hour, and then the spindle speed decreases linearly to 7,650 r.p.m. in a time of approximately 730 minutes.
 9. Apparatus for drawtwisting yarns or filaments comprising: drawing means for drawing said yarns or filaments, a rotary spindle, a ring and traveller for winding said yarns or filaments delivered from said drawing means on to a rotating bobbin on said spindle to form a wound package thereon, the diameter of said package continuously increases during the winding thereof, and spindle speed adjusting means for adjusting the speed of rotation of said spindle independent of the speed of said drawing means and including a speed-programing element defining a predetermined spindle speed program for controlling said spindle speed adjusting means, whereby at the commencement of and during an initial time interval of the build of a package said spindle runs at a speed lower than a predetermined maximum spindle speed, during an initial portion of the build said spindle speed gradually increases to a maximum spindle speed, and then said spindle speed gradually decreases throughout at least part of the remainder of the build of said package.
 10. Apparatus according to claim 9, wherein said programing element defines a spindle speed program in which the spindle speed increases during said initial time interval of the build, and said initial time interval representing not less than 4 percent of the total package building time.
 11. Apparatus according to claim 9, wherein said programing element defines a spindle speed program in which the spindle speed increases during said initial time interval of the build, and said initial time interval representing not less than 7 percent of the total pAckage building time.
 12. Apparatus according to claim 9, wherein said programming element defines a spindle speed program in which the spindle speed increases during said initial time interval of the build, and said initial time interval is 1 hour or more.
 13. Apparatus according to claim 9, wherein said programing element defines a spindle speed program in which the spindle speed decreases throughout the whole of the said remainder of the build of the package.
 14. Apparatus according to claim 9, wherein said speed-programing element defines a spindle speed program in which the spindle speed increases at a constant rate during said initial time interval of the build and decreases at a constant rate during the whole of the said remainder of the build of the package.
 15. Apparatus according to claim 9, wherein said yarn or filament drawing means is arranged to deliver drawn yarns or filaments at a constant delivery speed.
 16. Apparatus according to claim 15, wherein said programing element defines a spindle speed program wherein said drawing means provides a delivery speed of the drawn yarns or filaments substantially equal to 3000 feet per minute, the spindle speed increases linearly from 8,250 r.p.m. to a maximum spindle speed of 8,350 r.p.m. during said initial time interval, and the spindle speed decreases linearly throughout the remainder of the build of said package to 7,650 r.p.m., said initial time interval is substantially 1 hour, and the remainder of the build of said package is substantially 730 minutes.
 17. Apparatus according to claim 9, wherein said speed-programing element is removably mounted in said apparatus part of said speed adjusting means so that it can be replaced by another speed-programing element defining an alternative predetermined spindle speed program.
 18. Apparatus according to claim 9, wherein said programing element comprises a rotary cam which rotates once during each package build and which has a profile representing said program, and said spindle speed adjusting means further includes a control element engaging with said programing element to vary the spindle speed in accordance with said program. 